Short wave radio system



u y 9, 1940- G. c. SOUTHWORTH sHdRT WAVE RADIO SYSTEM Filed Sept. 12,1934 6 Sheets-Sheet l m W 3% m W W A .6

July 9, 1940.

cs. c. SOUTHWORTH SHORT WAVE RADIO SYSTEM Filed Sept. 12, 1934 6Sheets-Sheet 15 IIQVENTOR 6 6'. Sou k worl/z ATTORNEY July 9, 1940. e.c. SOUTHWORTH SHORT WAVE RADIO SYSTEM Filed Sept. 12, 1934 6Sheets-Sheet 4 'lIIIIIIIIIII/IIIIIIIIIIIA INVENTOR 6. 6: Soul/aworl/zATTORNfi July 9, 1940.

a. c; SOUTHWORTH SHORT WAVE RADIO SYSTEM Filed Sept. 12, 1934 6Sheets-Sheet 5 'INVENTOR G C Soul/2 worf/z afipw ATTORNEY July 9, 1940.G. c. SOUTHWORTH SHORT WAVE RADIO SYSTEM Filed Sept. 12, 1934 6Sheets-Sheet 6 Receiver 409 INVENTOR 61 C. SOMkl UOFLk @414.

ATTOPNFY Patented July 9, 1940 UNITED STATES PATENT OFFICE SHORT WAVERADIO SYSTEM Application September 12, 1934, Serial No. 743,753

69 Claims.

An object of my invention is to provide new and improved apparatus and acorresponding method for transmitting and receiving electromagneticwaves of very high frequency. Other objects are to establish a directionof maximum intensity in such waves and to practice directionalselectivity in their reception. Another object 18 to generate highfrequency electric waves in a dielectric guide and radiate them inspace. Other objects have to do with attaining directional intensity andselectivity by means of arrays of unitary radiators and receptorsenergized in proper phase and intensity relation. In the practice of myinvention waves of different types may be employed, electric ormagnetic, symmetric or asymmetric, using these terms in the senses to beexplained presently. In some principal examples of practice inaccordance with the invention electromagnetic waves are radiated fromthe open end of a dielectric guide comprising a metallic pipe or fromlateral openings in such a guide, or radio waves are received throughsuch open end or openings. Other embodiments feature metallic horns forradiating or intercepting waves and their use in conjunction withdielectric guides and metallic chambers for improving and modifying thedirectional characteristics thereof. In one embodiment of my invention awave front may be formed in a dielectric guide medium from a pluralityof simple component waves and then launched from that medium into space.In one aspect my invention involves an intimate combination of a vacuumtube with a dielectric wave guide whereby the waves are generated andlaunched with the desired type and frequency. Other aspects of theinvention involve shaping the wave front by means of refracting mediaand securing polarization in a proper desired transverse direction.Among the more specific applications of my invention disclosed hereinare direction finders and range finders. All the foregoing objects andaspects, and many other objects and advantages of my invention willbecome apparent on consideration of a limited number of specificembodiments of the invention which I have chosen for presentation in thefollowing specification and the accompanying drawings. It will beunderstood that this disclosure has relation principally to thesespecific embodiments of the invention and that its scope will beindicated in the appended claims.

Referring to the drawings, Figure 1 is a diagrammatic vertical sectionof a radiator having its principal intensity in all the directions of alike Fig. 3 with the salient distinction that the radiator is aconductor guide instead of a dielectric guide. Fig. 5 is a verticalsection of a dielectric guide radiator with a directional intensitydiagram. Fig. 6 is a. diagram corresponding to Fig. 5 but withsuppression of part of the directions of maximum intensity. Fig. '7 is adiagram corresponding to either Fig. 5 or Fig. 6 showing how energy maybe applied at the middle of the guide. Fig. 8 is a diagram showing unitssuch as in Figs. 5, 6 and 7 assembled in a directive diamond radiator.Fig. 9 is a diagrammatic vertical section like Fig. 3 but with variationof diameter of the guide instead of the use of metallic bands as in Fig.3. Fig. 10 is a horizontal section on the corresponding line of Fig. 9.Fig. 11 is a diagrammatic vertical section of a radiator consisting of ametal sheathed dielectric guide with windows to give radiation on oneside only. Fig. 12 is a horizontal section on the corresponding line ofFig. 11. Fig. 13 is a diagrammatic horizontal section of an array ofunits like the one shown in Figs. 11 and 12. Fig. 14 is a frontelevation of the same array. All the foregoing figures have relation tosymmetric electric waves in the dielectric guide or guides. Fig. 15 is adiagrammatic vertical section of a radiator for symmetrical magneticwaves. Fig. 16 is a horizontal section on the corresponding line of Fig.15. Fig. 17 is a section on the corresponding line of Fig. 15 lookingup. Fig. 18 is a. section on the corresponding line of Fig. 17. Fig. i19 is a diagrammatic vertical section of a radiator for asymmetricelectric waves. Fig. 20 and Fig. 21 are sections on the correspondinglines of Fig. 19. Fig. 22 is a directional intensity diagram in ahorizontal plane for the radiator of Figs 19, 20 and 21. Fig. 23 is adiagrammatic vertical section of a radiator for asymmetric magneticwaves. Fig. 24 is a horizontal section on the corresponding line of Fig.23. Fig, 25 is a perspective view showing the metallic conductor systemregarded as built up of a rowof'units. Fig. 31 is a unitary radiatorconsisting of a dielectric guide having a metallic shell. Fig. 32 showsthe same thing more in structural detail and with facilities forcertain'adiustments. Fig. 33 is a diagrammatic cross-section of theradiator shown in Fig. 32.. Fig. 34 is a diagram showing the circuitconnections for the vacuum tube employed in the device of Figs.32 and33. Fig. 35 is an axial section of a dielectric guide in the form of aflaring horn adapted to give directivity of transmission or to secure aproper electrical impedance match, as desired. Fig. 36 corresponds withFig. 35. except that the flare of the horn is according to a somewhatdifferent law. Fig. 37 is a transverse section of the horn of Fig. 35showing the lines of electric and magnetic force. Figs. 38 and 39 arecorresponding transverse sections showing alternative shapes. Fig. 40 isan axial section of a dielectric guide radiator with means to shape thewave to give it a fiat wave front. Fig. 41 is a diagram showing the useof concave reflectors to give a fiat wave front with a radiator of thetype of Fig. 31. Fig. 42 is a diagrammatic perspective view of an arrayof units of the type shown in Fig. 31. Fig. 43 is a ,vertical sectionthrough one column of units comprising an array as in Fig. 42. Fig. 44is a view partly in front elevation and partly in section of the samecolumn of units shown in Fig. 43,

together with certain associated elements. Fig. 45 is a horizontalsection through one of the columns of Figs. 43 and 44. Fig. 46 is anelevation showing adjustable covers for the opening in one of theradiator units. Figs. 47, 48 and 49 are horizontal sections at differentheights as indicated in Fig. 43. Fig. 50 is a set of vector diagrams towhich reference will be-made in explaining the mode of operation of thesystem of Figs. 43 to 49. Fig. 51 is a vertical section showing adielectric guide radiating upwardly in combination with a conicalreflector to change the radiation to substantially horizontal in alldirections. Fig. 52 corresponds to Fig. 51 with some modification ofdetail. Fig. 53 is a diagram of a burglar alarm system. Fig. 54 is ahorizontal section of a rotatable direction finder. Fig. 55 is avertical section of a modified rotatable direction finder. Fig. 56 is atop plan view of a rotatable range finder. Fig. 57 is an elevation ofthis same range finder. Fig. 58 is a diagrammatic top plan view of arange finder operating on a somewhat difierent principle.

This application is to some extent a continuation of my application,Serial No. 661,154, filed March 16, 1933, and of my application, SerialNo. 701,711, filed December 9, 1933, which issued on September 13, 1938as U. S. Patents No. 2,129,711 and No. 2,129,712.

In my aforementioned applications there are disclosed systems for theguided transmission of ultra high frequency electromagnetic waves 1through rods of dielectric material, metallic pipes containing only airor some other dielectric medium, and other wave guiding structuresproviding a dielectric path within a bounding medium of differentelectromagnetic properties. Such wave guides I have chosen to calldielectric guides. In accordance with these prior disclosures and aswill appear hereinafter, the guided waves may assume different forms ortypes each having a characteristic spacial distribution or pattern ofthe component electric and magnetic fields. In all examples heretoforeencountered in practice it has been found that for any partlcular typeof wave in any particular dielectric guide there is a critical orcut-off frequency, more or less sharply defined, which must be ex'-ceeded for wave power to be transmitted through an indefinite length ofdielectric guide. The cutoff frequency depends on the index ofrefraction of the dielectric medium and on the transverse dimensions ofthe guide, the diameter in the illustrative case of a guide of circularcross-section, and the velocity of propagation or the wave length withinthe guide is likewise significantly dependent on these factors. Itwillbe evident that separate conductors for the go and return fiow ofconducting currents, as in an ordinary wire line system, is notessential in a dielectric guide system.

Referring to Fig. 1 of the present case, the

numerals 2 and 3 designate a conductor pair; one of the two conductors,2, being a cylindrical shell, and the other conductor 3 being a rodlying in the axis of the shell 2. High frequency electromotive forcesare applied from the source I across the lower ends of the conductors 2and 3, and corresponding current waves travel up along the coaxialconductor system 23. The lines of force of these electric wavesprogressing up the coaxial conductor system 2-3, are directed radiallyand alternately outward and inward as the waves pass a fixed point.

At the top of the conductor pair 23, the axial core conductor 3 isexpanded into a cone 5, and the cylindrical conductor shell 2 isexpanded into a corresponding furmel 4, the cone 5 and the funnel 4being spaced apart all around, and this space being a continuedexpansion upward of the space between the conductors 2 and 3. In ahorizontal' section at any height, the .ratio is constant for the radiusof the outer surface of the inner conductor 5 and the radius of theinner surface of the outer conductor 4.

The cone 5 has a flat metallic base I on top, and in the same planetherewith it is surrounded by a fiat annulus 6, the central disc I andthe fiat annulus 6 being spaced by an annular gap 8, as seen in Fig. 2.It will readily be seen that the lines of force which extend radiallybetween the conductors 2 and 3 will pass up between the flaring members4 and 5 and will arch across between the plates 1 and B as indicated atH in Fig. 1. All of the lines shown in Fig. 1 are electric lines offorce; generally the magnetic lines are circles around the vertical axisof the coaxial component of the electric force in the direction ofpropagation, this type of wave is called an electric wave; and becauseit is the same in all horizontal directions around the axis it is calledsymmetric.

Standing on the plates or electrodes 6 and 1 is a cylinder 9 ofdielectric material. This may be regarded as a short section ofcylindrical dielectric guide with vertical axis. Surrounding the base ofthe dielectric guide 9 is a conductive platform l0.

The waves in the dielectric guide 9, represented by the lines ofelectric force H, are broken ofl in loops and progress upwardly asindicated at l2. These lines of electric force extend out into the spacesurrounding the guide 9 and form completely closed loops as'indicated atl3. These loops move out horizontally, as well as upwardly, and aredetached as electromagnetic waves and radiated into space as indicatedat I. shown at M in Fig.1 are samples of such line;

The lines aaoepaa lying all around the axis of the guide 9 on everyside.

Generally the velocity of propagation in the material of the guide 9will be less than in air or empty space. By a proper choice of diameterand material this veloclty' may advantageously be made about one-halfthat of ordinary light. This means that the wave length in the guide isone-half that in the surrounding medium. A specific set of data givingsatisfactory results is to employ an operating frequency of 1,750megacycles and make the guide 9 of an insulating material which has adielectric constant of about 10, and hence. an index of refraction ofabout 3.16, which is the square root of 10. The wave length in the guidedepends both upon the diameter and the index of refraction. The diameterof the guide-radiator 9 is chosen at 6.54 cms. so that the wave lengthin the radiator shall be about onehalf that in the surrounding medium.The length or height of the cylinder 9 is about 4.5 cms., which isslightly more than one-half the wave length in the dielectric. All thesedimensions and others may be in some degree determined by anexperimental adjustment.

The apparatus of Fig. 3 differs from that of Fig. I principally in thatthe cylindrical dielectric guide 9 with vertical axis, has been muchextended in a vertical direction and surrounded with a metallic band I5at its base and other metallic bands I6 equally spaced along its height.As the waves represented by the lines of force I I and I2 progressupwardly in the guide 9 of Fig. 3, part of their energy is radiated intothe surrounding space between successive metal bands I5 and I6 asindicated at I3. But, as the waves I2 move up, the ends of the lines offorce rest on a metallic band such as I6 as indicated by the lines I1,and in this state there is no radiation in the surrounding space. Thenat the next stage higher up, between two successive metallic bands I6,there is more radiation, and so on. Farther out, all around, the linesof force such as I3, become detached and linked end to end to form thewave front I4. Presently these lines straighten out vertically and theradiated wave takes the form shown farthest out from the axis in Fig. 3.Vertical sections containing the axis of the guide 9 of Fig. 3 wouldshow the same configuration of lines of force in any horizontaldirection.

Assuming that the material and the dimensions are chosen in Fig. 3 sothat the wave length in the guide is half that in the surroundingmedium, then the radiating bands between the metal bands I6 will bespaced at intervals equal to the wave length in the guide. Thus, theywill oscillate in the same phase, as indicated in Fig. 3.

In Fig. 4 there is shown a metallic conductor antenna 9' with likespaced cylindrical metal shields I6 along its length. These shields I6are each as long as the alternating spaces between them. The frequencyof the source I being such that the wave length in the conductor istwice the length of a shield, it follows that the unshielded radiatingparts of the antenna 9' are in like phase and these parts contributealike to send a horizontal beam of radiation, without interference fromthe shielded parts. The shields I6 may be supported conveniently on theantenna 9, especially if the latter is supported as a tower standing onan insulating base at its lower end. .In the normal operation of thesystem of Fig. 4, there will be a voltage node at the middle of theheight of each shield I 6'; therefore the system will be electricallyunchanged to any substantial degree by metallic supporting connectionsas shown at I6" in Fig. 4.

A guide such as 9 of Fig. 3, but without the metal bands I6, is shown inFig. 5 capped by a metallic plate ll. Standing waves are set up in thisguide and they build up an interference pattern to give dlfierentintensities in different directions. The loops of Fig. 5 are the loopsof a polar intensity diagram. These show that the greatest intensitiesare nearly upward and downward, inclined a little to the axis of theguide. The diagram of Fig. 5 is based on the assumption that thedielectric losses in the guide 9 are relatively small, and the diameterof the guide is so chosen as to make the radiated component not toolarge. Suppose, on the other hand, that radiation produces considerableloss, and in addition, the cap as at I9 in Fig. 6, is of semi-conductivematerial so as to absorb all the wave power incident upon it from withinthe guide, then there will be no reflected wave at this end of the guideand no standing waves in the guide, and the polar intensity diagram willhave the shape shown in Fig.

It is assumed in connection with Figs. 5 and 6 that energy is fed intothe guide 9 at its lower end, but the energy may be applied at themiddle of the length of the guide according to the plan indicated inFig. 7.

Referring to Fig. 8, this shows four guides 9" connected in diamondshape and all supplied with energy from source I through connection 2.By virtue of the energy sink I9, there is no reflection of energy. Eachof the four guides has a principal loop of its polar intensity diagramas shown at I8 in Fig 8. These loops I8 have their axes parallel and addvectorially with full resultant efiect. Other loops, not shown in Fig.8, have their axes in various directions and add vectorially to cancelout to a very great extent.

Instead of suppressing radiation at points along the height of the guide9 by means of metal bands I6 as shown in Fig. 3, this effect may beattained as shown in Fig. 9 by spaced enlargements of the guide as at20. Within each enlarged part 20 the lines of force are closed withinthe guide, but within each reduced part they break out into thesurrounding space and break off and link together end to end to give theconfiguration indicated at I4.

Where the diameter is increased as at 20, this has the effect ofreducing the speed of propagation along the guide which requires theradiating parts of the guide to be brought nearer together.

As shown in Figs. 11 and 12, the guide 9 may consist of a dielectriccore within a cylindrical metallic shell, which is continuous except fora series of vertically spaced openings or windows 22. Around each window22 is an outwardly directed flange 23 which partakes of the nature of ahorn. This radiator sends out such waves as do the radiators of Figs. 3and 9, but only on the side having the windows 22 so that in ahorizontal plan view the radiation is as seen in Fig. 12.

Here and elsewhere throughout this specification the word radiate andits derivatives do not necessarily imply that there is divergence, suchas shown in Fig. 12.

-Radiation may be enhanced in one horizontal direction, with little orno divergence, by arranging radiators such as in Fig. 3 or Fig. 9 tostand side by side. In this case, an appropriate spacing between themwould be half the wave length in air, though it may be as much as 0.7times the should all be operated vatlon as shown in Fig. 14. If theradiation from each vertical row of openings is of the character shownin Fig. 12, the interference pattern produced will give a plane wavefront, and accordingly, the radiator will be more narrowly directed inintensity than in Fig. 12.

The waves considered heretofore have been of the type which I callsymmetric electric, with electric lines of force as shown by thecontinuous lines in Figs. 1,3, 9 andll. Figs. and 16 the wave type issymmetric magnetic, the lines of electric force here being horizontalcircles coaxial with the vertical axis of the radiator 9. These wavesare called magnetic because the lines of magnetic force have a componentin the direction of propagation, and symmetric, because they lie on allsides around the vertical axis of the radiator. The radiating element 9of Fig. 15 is about 60% larger than the cor= responding element of Fig.l, for the same dielectric material and the same wa've frequency. Thesource I supplies alternating electric currents of high frequency overthe coaxial conductor system 23. At its upper end the tubular conductor2 has two opposite radial arms 24 and 28 (see Figs. 17 and 18) whichextend around through the parts 242526 and 28-21-26', and meet on theextremity of the axial core conductor 3. In other words, the apparatusindicated generally in Fig. 15 by the reference numeral 29, and shownmore in detail in the plan view looking up, of Fig. 17, is a figure-8conductor with one cross-branch connected to one conductor 2 of thecoaxial conductor system, and the other crossbranch connected to theother conductor 3 of the coaxial conductor system.

The waves that go up the coaxial conductor system 23 of Fig. 15, in theform of radially directed lines of force, are re-shaped by the 8- shapedmember 29 and enter the dielectric guide 9 in the form of horizontalcircles. These are radiated out laterally into space as shown by thediagrams of Figs. 15 and 16. Suppose that at a certain instant the shell2 is positive at its upper end in Fig. 15 and the core 3 is negative;corresponding currents will flow in both arcs 25 and 21 directed thesame way around the axis. Thus, it will be seen how the circular linesof electric force are thrown off and up into the dielectricguide-radiator member 9. In the same way that the elements of Fig. 1 maybe arrayed to give horizontal directivity as in Figs. 3,9, and 11. somay the elements of Fig. 15 be arrayed, likewise, for the same-purpose.1

For the radiation of asymmetric electric waves, two parallel conductorrods 33 are extended vertically upward from the source I as shown inFig. IS. A high frequency alternating current is impressed across theseconductors at their lower ends. At their upper ends they are terminatedby the two plates 34 having the shape shown in Fig. 20. The lines offorce extend across these plates 34 as indicated at 31 in Fig. 19. Also,some lines, as at 38, extend across from each electrode 34 to theannular bed plate 35. As the lines 31 and 38 become detached and floatup to 39 and 46 respectively, the latter lines expand laterally as at 4|and spread out horizontally with the usual velocity of light in freespace. The lines of In the radiator of force I! and 4ll are gatheredcloser together within the space marked in Fig. 21 with the numeral 43,somewhat as if there were a conductor at this 1 the two plates 43 andspaced one-half wave length apart and oscillating in opposite phase.

The horizontal intensity diagram for the system of Figs. 19, and 21 isshown by the curves in Fig. 22. These indicate two maxima of intensityin two opposite horizontal directions with null intensity at rightangles thereto. The same radiation of power measured in watts will givemuch more intensity in a preferred direction and its opposite, then whenthe same power is distributed uniformly in all horizontal directions. Ifthe same power is radiated in both cases, the gain in the preferreddirection with the characteristic 44 of Fig. 22 is about 3 decibels.This means that 1 watt of power is as eflfective in the preferreddirection as 2 watts would be when radiated uniformly in all directions.The antenna of Figs. 19 and 21 is very useful when it is desired toavoid interference with stations in lateral directions by suppressingradiation in those directions. The units of Figs. 19 and 21 can becombined in arrays as heretofore described, to give enhanced directionalselectivity.

Radiation of asymmetric magnetic waves may be effected by the systemshown in Figs. 23, 24 and 25. Here the source I puts a high frequencyalternating current across the two parallel conductor rods 33 whichdiverge at their upper ends and are connected to two diametricallyopposite points of the horizontal conductor annulus 46. The lines ofelectric force extend substantially parallel with the diameter of theannulus that connects the upper ends of the two conductors 33. Theselines are propagated upwardly in the dielectric guide 9, and outwardlytherefrom, so that the wave shape pattern in plan view has theappearance shown in Fig. 24, in which the continuous lines representelectric lines of force and the dotted lines represent magnetic lines offorce. Since the magnetic lines have components in the direction ofpropagation, this is called a magnetic wave, and aglance at Fig. 24shows why it is called asymmetric. The elements of Figs. 23, 24 and maybe arranged in arrays to give directional selectivity as has beendescribed for the other kinds of elements heretofore.

In the system of Figs. 26 and, 27, asymmetric magnetic waves arepropagated along the guides 53 with their lines of electric forceextending across horizontally as indicated by the double headed arrows55 at the bottom of Fig. 26. Each guide shell 53 has regularly spacedtransverse openings 54 connecting with the block of dielectric guidematerial 50 standing above. At each opening 54 some lines of electricforce escape through the opening upwardly and progress upwardly as wavesin the block of dielectric material 50. This material 50 is encased in ametal shell 5| having a series of spaced horizontal slots in one face.The lines of force escape through these slot openings as shown at 58,and link together end to end as at 59, to give waves having a plane wavefront with the direction of propagation horizontally to the right asviewed in Fig. 26.

The design of Figs. 26 and 27 and the mode of operation, may beapprehended by considering a series of cylindrical units side by sidewith their axes parallel in one vertical plane, as seen at 50 in Fig.28, which is a horizontal section. From each such unit 50 the asymmetricmagnetic waves escape as indicated by the lines of electric force. Ifthese units are enlarged, we make the transition from Fig. 28 to Fig.29. Further enlarging the units, so that they unite to form one largerectangular block 50, we have the diagram of Fig. 30 corresponding to ahorizontal section through the guide shell 5| of Figs. 26 and 27.

While the system of Figs. 26 and 27 has been described for asymmetricmagnetic waves, it could obviously be modified and adapted for othertypes. The openings 54 in the two guides 53 are staggered so that theguide material above them shall be utilized as nearly uniformly aspracticable, and to the utmost advantage. These openings 54 are spacedalong each guide 53 at wave length intervals as measured in the guide,so that the waves will enter the guide material 50 in like phase allacross its lower part. The slots 52 are spaced at one or an integralnumber of wave lengths as measured in the guide material 50 so as to getall parts of the radiated wave front in like phase.

Another kind of a unit radiator is shown in Fig. 31. Here there is acylindrical metal shell 62, more particularly a cylindrical shell ofcircular cross-section, closed across one end with a metal wall 69.Inside, at 63, is an oscillation generator onnected to diametricallyopposite points of the shell 62. This shell 62 may be filled withparafiin or any other suitable dielectric. When a dielectric guidecomprises an enclosing metallic sheath, the dielectric may be anysuitable medium, and as an important special case, it may be emptyspace, or its equivalent. air Thus in Fig. 31 the dielectric mediumwithin the shell 62 may be empty space or air Accordingly, a hollowmetal pipe may be made to function as a dielectric guide. The lines ofelectric force such as 65. extending across, parallel to a diameter,will establish asymmetric magnetic waves which will be propagated alongtoward the open end of the shell 62 and radiated therefrom, as indicatedby the group of lines 66 in one direction, 61 in the opposite directionand 68 again in the first direction. The oscillator 63 mayadvantageously be placed at such distance from the end wall 69 that thewaves reflected therefrom will reenforce the waves that proceed directlyto the right from the oscillator.

A practicable form of the radiator of Fig. 31 may be made of a 12-inchlength of pipe having its diameter 5" and containing air as thedielectric material. Operated at a frequency of 1,750 megacycles thisgives a wave length in free space of about 17 cms.

In referring to the element 63 as an oscillation generator I contemplatethat its frequency determining elements may or may not be included. Thusin Fig. 31, the frequency may be dependent, in some degree, on thedimensions of the guide around the source 63. Similarly, athree-electrode vacuum tube oscillator combined with frequencydetermining conductive circuits comprising inductance or capacity orboth may be taken to be only the tube or the combination of the tube andthe circuits. In any case, if it is important to know whether the termoscillation generator includes the complete frequency determiningelements, I endeavor to make this clear in the context.

This same kind of a radiating unit of Fig. 31 is shown with certainfacilities for adjustment in Figs. 32, 33 and 34. The cylindrical sidewall 32 has a telescoping extension 62 adjustable by means of a rack andpinion, and a movable end wall 69, also adjustable by rack and pinion.

Oscillation generator III is a three-electrode vacuum tube having atransverse filament II, a grid I3 in the form of a helix around thefilament II as axis, and a cylindrical plate anode 12 outside the gridand having the same axis. This vacuum tube 10 is fixed by the support10' in the center of the radiator. The direct current for heating thefilament comes in over the diametrically opposite conductors 11 and 18.The direct current across the plate and filament is applied through theconductor 16 which lies beside the conductor ll. Therespective ends ofthe grid 13 are connected by means of the conductors l4 and 15 todiametrically opposite points of the shell 62, the diameter for thesetwo points being at a right angle to the diameter for the conductors I1and I8.

. At the very high frequencies involved, oscillation generator 10operates most effectively and advantageously when tuning devices areplaced along its associated conductors. These tuning devices are shownin Fig. 33. They exclude from the filament and plate leads certainparasitic high frequency currents which have been found to have verydeleterious effects. The conductor 14, for example, lies along a radiusof the shell 62. Around it, as axis, there is a cylindrical shell 80.The metallic plunger BI is longitudinally displaceable, and fills theannular space between the axial conductor 14 and the surroundingcylindrical conductor and establishes conductive connection betweenthese two members. This metallic plunger BI is connected by a tube 82 tothe handle 83 by which it may be displaced inwardly or outwardly. Thus.the effective length of the concentric conductor system between theplunger 81 and the end 80 of the tube 8|] may be adjusted as desired. Inthis space a system of standing waves for a coaxial conductor pair willbe set up and the most advantageous tuning secured in this way. All fiveconductors l4, 15, I6, 11 and I8 are connected for high frequencies tothe shell 62, this connection being made through the condensers 84 incertain cases so as to block the direct currents. Where the condensers84 are employed, insulating bushings 19 are used.

Of the five conductors leading to and from the vacuum tube, all exceptthe grid leads lie along equi-potentials of the electric field. For aspecific example of the system shown in Fig. 32, a filament current of 5amperes may be used with the grid voltage at 3'75 volts and the platevoltage at 40 volts. It is proper to regard the wave power as residingin lines of force produced by the acceleration of electrons back andforth through the spiral grid. These lines of force operate in virtue ofthe inductance property of the spiral grid to produce a substantialdifference of potential between its opposite ends which is communicatedto the diametrically opposite points on the inner wall of the shell 62to which the ends of the grid are connected.

In such a device as that of Fig. 31, the waves are formed within aconductive chamber, and thereafter they are radiated out intoneighboring space and away. To bring the waves to the desired form anappropriate shape may be given to the surrounding conductive chamber, asfor example in Fig. 35. Here, to secure directivity,

be more narrowly directive. In other words, the

a helicoidal form by a quarter turn twist.

fPoynting vectors representing theflow of power will be more nearlyparallel. The corresponding lines of force are shown by the transversesection of Fig. 37 in which the continuous lines are electric and thedotted lines are magnetic.

of two functions. As one of these functions, it may be a wave shaping ordirective device as has been explained. Theother possible'function is.

to serve as an impedance matching device. In the latter case it may beused to terminate a wave guide in its own characteristic impedance. Itmay have its contour modified as shown in Fig. 36, that is, thelongitudinal wall section may be concave inwardly instead of convexoutwardly.

It may be advantageous in shaping the wave front to depart from thecircular section of Fig. 37, to an oval or elliptical shape, as in Fig.38, or a rectangular shape as in Fig. 39.

Whatever the dielectric within the unit 62 of Fig. 35, it may behelpful, in order to get a plane wave front, to place across the openinga lens 64' of material having a different index of refraction; this isshown in Fig. 40. If the wave front is convex within, as at 64, then thelens should be convex or concave, according as its index is greater orless than at 64.

Another way to flatten the wave front from the open end of a guide 64 isbythe use of two reflectors shaped and arranged as shown at 64" and 64"in Fig. 41.

Unitary radiators such as shown in Fig. 31, may be assembled in anantenna array to give a decidedly directional effect, as shown in asimple diagrammatic sketch in Fig. 42. Here the units are mounted in aframe 89 which is supported on rollers so that it can be turned inwhatever direction the maximum intensity is desired. This frame 89 maybe a solid block of metal, or a skeleton frame, or it may be of sheetmetal with open end cavities as radiators. In the latter case theradiator units can be energized from a common source in the mannerillustrated'in Figs. 43 and 44. Fig. 43 is a vertical cross-section downthrough a column of the units, and Fig. 44 is a section partly inelevation at a right angle to the section of Fig. 43. The generator 63sends asymmetric magnetic waves along the guide 62 to the right, asviewed in Fig. 44. From this horizontally extending guide 62,branchguides 9| extend upwardly. These are spaced a wave length apart.In the lower end of each vertical branch guide 9I- is a metal plate92'which is given This is indicated by the sections in Figs. 47, 48 and49. This changes the direction of polarity of the waves as they ascendin the branch guides 9I, adapting them for further cooperation, as

will be described presently.

At intervals of a wave length along each vertical guide, there arewindows or openings 93 opening into horizontal branch guides 94, eachwith a telescopically adjustable extension part 95. The windows 93permit some of the lines of force to escape through them as showndiagrammatically in Fig. 45. They may be covered by sliding metal platedoors 96 in guides 91 as shown in Fig. 46, so as to adjust the size ofthe openings.

From each unit 94-95 the waves come out in The horn of Fig. 35 mayperform either or both like phase and'coalesce to form a plane wavefront which is radiated with a high degree of directional intensity.

' Referring to the twisted helicoidal member 92 of Figs. 47, 48 and 49,this works best when its end on which the waves are incident, isperpendicular to the lines of electric force of that wave. This relationis shown by the last of the 5 vector diagrams of Fig. 50. -In each ofthese diagrams the line V. indicates the direction of the edge of theseptum on which the waves are incident, the arrow V1 represents thedirection of the electric lines of force at this point, and the line Vtrepresents the direction of the electric lines of force at the oppositeend of the septum. The transmitted wave is always rotated degrees in anyone of these five cases, but it has its greatest magnitude in the casethat has been described, most particularly shown. at the right of Fig.50.

For a frequency of 1,750 megacycles which corresponds to a wave lengthin free space of about 17.1 cms., the vertical branches may be spacedappropriately at about 22.2 cms. If each radiating unit is made about12.5 cms. in diameter, then the horizontalseparation from rim to rim ofthe adjacent units will be about 9.7 cms. This wave lengh within theguide of 22.2 cms. may be obtained by making it about 8 inches indiameter when using air for the dielectric. If it is desired to radiateelectric waves in all directions horizontally but without the spreadingof intensity at angles up or down, a unit of Fig. 31 may be employed asindicated at 62 in Fig. 51, that is, having its open end directedupwardly with a conical reflector 98 above it. The dotted arrowsrepresent the directions of progression of the electric wave, and thecontinuous line arrows represent a line of force as it makes suchprogress. Thus, we see a line of force progressing along the guide 62from 99 to I00. At the reflector 98, it is shown partly reflected andpartly not yet reflected, the reflected part being IOI and the part notyet reflected being I02; after reflection the wave advances horizontallyand we see it at a later stage at I03.

The upper end of the unitary radiating wave guide may be flanged as atI04 in Fig. 52, and the conical reflector may be given a propermodifying shape as at 98' so as to hold the waves to the desired lateraldirection of maximum intensity.

A radiator such as that of Fig. 51 or Fig. 52 will generally be bestsuited for operation with symmetric type waves, electric or magnetic.Such a radiator is adapted for a radio beacon when it is desired to havethe emitted radiation distributed all around in a horizontal plane.

While the foregoing descriptions have had'relation principally totransmitters, it will be readily understood how the principles involvedare applicable for receivers.

The rectangular outline of Fig. 53 represents a room in horizontalsection equipped with a burglar alarm system. A transmitter T like thatof Fig. 35 is set in one side wall and a corresponding receiver R is inthe opposite side wall. Double oblique mirrors M and M" are provided toestablish the ray paths shown by dotted lines with reflection at A andB. The-path via A is longer than that via B by an odd number of halfwaves so'that normally there is a null effect. on the rereceiver R. Butif any one of the paths indicated by the four dotted line segments isinterrupted, as by an intruder, there is an unbalance at R and an alarmsignal is given on the device S.

A direction finder is shown in Fig. 54. A receiver wave front isrepresented at I00. Two unit tubular guides, each a cavity typeresonator, are shown at I08 on the ends of transverse wave guides I01which are pivotally mounted at IIO so as to rotate around a verticalaxis. The received radiation in the guide unit I06 is admitted bywindows I06" to the transverse guides I01. By means of the reflectorsI09 the radiation from the guides I 01 is directed into the main guideI08 and thence to the receiver I 09.

The crests and troughs of an approaching wave to be received, arerepresented by the continuous and dotted lines, respectively, at I05. Ifthe apparatus is turned so as to be directed accurately to receive thesewaves, the effects in the two resonators I00 will be in like phase andthere will be a maximum of received intensity in the receiver I09. Thiswill be 3 decibels higher than if only one of the chambers I06 had beenoperative.

A modification is shown in Fig. 55 in which the two resonating chambersI06 connect with the vertical main wave guide I08 which has a joint III,so that the receiver I09 can remain stationary while the rest of thedevice rotates, and the angle can be read off on the scale at I I2.

In either form of the device shown in Fig. 54 or Fig. 55, there will beseveral maxima and minima of intensity corresponding to a difference ofwave path of an integral number of half wave lengths. Generally, theintensity in the receiver will be less than when this difference iszero. However, to be certain that the maximum intensity depended uponcorresponds to zero difference in wave path, one of the chambers is shutoff by a butterfly valve such as H3 in Fig. 55, and the device isrotated through a wide angle to get the direction of maximum intensitywith a tolerable degree of approximation. Then the valve H3 is openedand finer adjustments are made about the position previouslyascertained, to get the direction more exactly. Two valves H3 areprovided, one on each side as shown in Fig. 55, so that the electricalpaths on the two sides will be matched and balanced.

A range finder is shown in plan view on Fig. 56, and in elevation inFig. 57. The two resonant chambers I06 are pivoted on the crossmemberI01. At the points H0 at the normal extreme of adjustment, the axis ofeach chamber I 06 will be at 90 degrees to the cross-arm I 01. Byturning the knob H9 at the scale, the interposed mechanism II8-Il'I- IIGII5 operates to incline the chambers I06 a little so that these anglesbecome less than 90 degrees. The approaching wave front will be circularwith its center at its source, and will be received with greatestintensity when the axes of the two resonating chambers I00 are directedalong respective radii of such circles. The scale at the knob II9 may becalibrated to read the range directly.

In the modified form of range finder shown in Fig. 58 three resonatingchambers are employed and the middle one I05 is adjusted forward orbackward to get a maximum intensity in all three such chambers combined.At this intensity the three chambers will be equally distant from thesource. With the source as center the are c is drawn with b as its halfchord or sine. The sagitta of the are c is the length a, and the rangeis a function of a in relation to b, so that from the adjustment of theintermediate resonating chamber I06 the range can be ascertained. Theformula is d=b /2a. If the wave length is 1 cm. the displacement of thechamber I06 between maximum and minimum intensity would be 0.5 cm. Thismeans that it would be easy to detect signal differences correspondingto sagittal differences as small as 0.1 cm. If the base b is 3 meters,then by substitution in the above formula we would get a distance to thesource of 4500 meters.

I claim:

1. The method of transmitting electrical effects from one place toanother place which comprises generating electromagnetic waves at theone place in a wave guide, said waves being of such character that theysubsist within said guide at any frequencies above a critical frequencydetermined in part by a'transverse dimension of said guide -but not atslower frequencies, passing said waves an appreciable distance throughsaid guide and radiating them therefrom to the other place.

2. A combination for effecting translation of energy between radio wavesof a given frequency and an electrical circuit, including a length ofwave guide that comprises a laterally bounded dielectric medium, theinterior of said guide being dielectrically connected with free spacenear one end for energy interchange with said radio waves, and meansnear the other end for energy interchange with said electrical circuit,said means being adapted for launching into said guide or receivingtherefrom guided electromagnetic waves of such characteristic fieldpattern that energy transmission between said means and said one end cantake place substantially at any frequencies exceeding a criticalfrequency functionally related to the transverse dimensions of saidguide but substantially only at such frequencies, said transversedimensions being such that the critical frequency lies below thefrequency of said radio waves.

3. A combination for effecting translation of energy between radio wavesand an electrical circuit, comprising a section of metallic pipecontaining a dielectric medium, the interior of said pipe having adielectric connection to free space at one end for energy interchangewith said radio waves, means at the other end of said pipe for energyinterchange with said electrical circuit, said means being adapted forenergy interchange with guided waves within said pipe of such characterthat substantial translation of energy between said radio waves and saidelectrical circuit takes place only at frequencies exceeding a high-passtransmission cut-off frequency dependent on the transverse dimensions ofsaid pipe.

4. A combination for effecting translation of energy between radio wavesand an electrical circuit, comprising a section of metallic pipecontaining a dielectric medium, the interior of said pipe having adielectric connection to free space at one end for energy interchangewith said radio waves, means at the other end of said pipe for energyinterchange with said electrical circuit, said means being adapted forenergy interchange with guided waves within said pipe of such characterthat substantial translation of energy between said radio waves and saidelectrical circuit takes place only at frequencies exceeding a criticalcut-off frequency dependent on the transverse dimensions of said pipe,said dielectric connection to free space comprising means for matchingimpedances.

5. In combination, a wave guide comprising a metallic pipe containingonly a dielectric medium, electrodes at one end of said guide, a

high frequency alternating current generator operatively connected tosaid electrodes, the frequency of said generator being sufliciently highrelative to a transmission cut-off frequency dedependent on an internaldimension of said pipe that progressive electromagnetic waves areestablished in said dielectric medium, said guide being open near itsother end to radiate said progressive waves into space.

6. In a radio transmission system, a wave guide comprising a metallicpipe containing a gaseous dielectric medium, and means for launchinginto said guide or receiving therefrom high frequency electromagneticwaves of such characteristic field pattern that the guide presents tothem the characteristics of a high-pass filter, theinterior of saidguide having an opening to free space at a distance from said means,whereby waves launched 'into said guide are radiated through saidopening into space or radio waves intercepted at said opening aretransmitted through said guide to said means.

7. A combination in accordance with claim 6 in which said pipe isopenended, thereby providing said opening to free space.

8. In combination, a generator of high frequency alternating currents, aconcentric con-,

ductor. system connected thereto, a wave guide consisting essentially ofa bounded dielectric medium the boundary of which separates said me-.dium from a medium having different electromagnetic characteristics, aterminal structure at one point connecting said conductor system withsaid guide to set up progressive electromagnetic waves in said guide ofa character such that they are readily transmitted through said guideonly at frequencies exceeding a critical frequency functionally relatedto a transverse dimension of said guide, said progressiveelectromagnetic waves being radiated into space at another point of saidguide.

9. In combination, a wave guide consisting essentially of a. metallicpipe, a high frequency alternating current generator and means couplingsaid generator and guide in energy transfer relation comprising aterminal structure adapted to generate in said guide progressiveelectromagnetic waves characterized in that there is a substantialcomponent of electric force in the direction of propagation and in thatthe field is symmetric about the axis of said guide, said pipe having anopening in at least one place for the radiation of said wavestransmitted therethrough, the distance between said coupling means andat least one of said openings being great enough that substantialradiation occurs only at frequenciesexceeding the transmissioncut-oiffrequency of said guide.

10. In combination, a wave guide comprising a metallicpi pe having anopen end, a metallic horn surmounting the said open end of said pipe,electrical circuit means at a distance from said horn in energy transferrelation with said pipe,

said means being adapted either for launching into said pipe ultra-highfrequency electromagnetic waves of such characteristic field patternthat the pipe presents to them the characteristics of a high-pass filteror for receiving waves of such field pattern established in said pipe byincoming radio waves intercepted by said horn, the frequency of thewaves so launched or received being substantially in excess of thetransmission cut-off frequency of said pipe.

11. In'a system for the radiation or reception of ultra high frequencyelectromagnetic waves,

a wave guide comprising a metallic pipe enclosing a dielectric medium,translating means within said guide adapted for the launching orreception of guided waves in which the electric field is roughlydiametral, said pipe having a dielectric connection to free space at adistance from said translating means such that wave propagation takesplace substantially only at frequencies exceeding a transmission cut-ofifrequency, and a signaling circuit connected to said translating means.

12. A combination in accordance with claim 11 in which said pipe isopen-ended, thereby providing said dielectric connection.

13. A combination in accordance with claim 11 in which one end of saidpipe is open and flared.

14. In combination, a wave guiding structure comprising a metallic pipecontaining only a dielectric medium, a source of high frequency currentand means within said guiding structure and coupled to said source forgenerating in said pipe progressive guided electromagnetic waves ofasymmetric magnetic type, the frequency of said source being greaterthan a critical frequency below which said waves are propagated, if atall, only with great attenuation, said pipe having an opening at a pointdistant from said generating means through which said waves are radiatedinto space.

15. In a system for radiating electromagnetic waves, a ,wave guidecomprising an extended body of dielectric of restricted cross-section,means for applying to said guide electromagnetic waves of a frequency sohigh as related to a transverse dimension of said guide that they arepropagated through said guide and radiated'therefrom, and meanssystematically spaced along said guide for inhibiting radiation so thatthe parts of uninhibited radiation are combined to give a directionallyselective effect,

16. In combination, a dielectric guide, means to generateelectromagnetic waves therein of frequency appropriate to itsdimensions, said guide being adapted to radiate correspondingelectromagnetic waves therefrom, and said guide comprising a metalsheath with regularly arranged openings therethrough for the radiationof electromagnetic waves and their combination with directionallyselective effect.

17. A radiator of electromagnetic waves consisting of a dielectric guidethat includes a 1 metallic sheath having a row of windows along one sidethrough which radiation may-occur so that the parts of such radiationwill combine to give directional selectivity, the transverse dimensionsof said guide being appropriate for dielectrically guided wavepropagation at the frequency of said waves.

18. A metal sheathed slab of dielectric material, a cylindrical metalsheathed dielectric guide adjacent to one edge of said slab, the sheathsbetween the slab and guide having inter- T connecting, regularly spaced,transverse slotsand the sheath of said slab having slots in one faceparallel with said guide, whereby electromagnetic waves of sufiicientlyhigh frequency in said guide go therefrom through the first. mentionedslots into said slab and then from the sufficiently high as related tothe transverse dimensions of said guide may be radiated from the openend.

20. A metal sheathed wave guide, a generator lying in its axis, saidgenerator comprising a space discharge device having cathode, anode andgrid electrodes, conductive connections from the respective ends of thegrid to diametrically opposite points of the metal sheath, said sheathhaving openings at the ends of a diameter at a right angle to thediameter of the grid connections, and cathode conductors passingrespectively through said openings.

21. A metal sheathed dielectric guide, a three electrode vacuum tubegenerator lying in its axis. said tube having a helical grid and acathode, conductive connections from the respective ends of the grid todiametrically opposite points of the metal sheath, said sheath havingopenings at the ends of a diameter at a right angle to the diameter ofthe grid connections, and conductors passing respectively through saidopenings for carrying current to heat said cathode.

22. A wave guide consisting essentially of a metallic pipe, a highfrequency oscillation generator within said pipe, a terminal structureconnected to said generator for producing progressive electromagneticwaves in said pipe of a character such that there is a criticalfrequency related to the transverse dimensions of said pipe separatingthe operative frequency range from a lower frequency range of zero ornegligible transmission, and low frequency leads through the wall ofsaid pipe to said generator, said leads lying in an equipotential locus.

23. A metal sheathed dielectric guide, a three electrode vacuum tubegenerator lying in its axis, said vacuum tube generator having afilament, a grid and a plate electrode, conductive connections from therespective ends of the grid to diametrically opposite points of themetal sheath, said sheath having openings at the ends of a diameter at aright angle to that of the grid connections. filament conductors passingrespectively therethrough and a plate conductor close to one of saidfilament conductors and insulated from said sheath.

24. A metal sheathed dielectric guide, a high frequency alternatingcurrent generator in its axis, a radial conductor to said generator, aspaced metallic sleeve around said conductor, and a connector betweensaid conductor and sleeve, said connector being longitudinallyadjustable for tuning.

25. An electromagnetic wave guide consisting essentially of a body ofdielectric enclosed within a metal sheath, a high frequency alternatingcurrent generator in its axis, a radial conductor to said generator, aspaced metallic sleeve around said conductor, and a conductive connectorbetween said conductor and sleeve, said connector being longitudinallyadjustable for tuning, and said sleeve passing through the sheath andbeing insulated therefrom.

26. A metal sheathed wave guide having one end open and flared, theother closed, and an alternating current generator electricallyconnected across two opposite points of the sheath near the closed end,said generator being adapted to operate at a frequency so high thatelectromagnetic waves may be radiated from the open flared end.

27. In combination, a dielectric guide consisting essentially of ahollow metallic pipe, means to generate electromagnetic waves therein offrequency appropriate to its dimensions, and an impedance matchingtermination for said guide adapted to radiate correspondingelectromagnetic waves therefrom.

. 28. A combination for the directive radiation of high frequencyelectromagnetic waves comprising an elongated metallically boundedchamber enclosing a dielectric medium, means for producinglongitudinally progressive guided waves in said chamber of a charactersuch that the velocity of propagation is a function of a transversedimension of said chamber, said chamber having an opening in the lateralboundary thereof for the emission and radiation of waves guided throughsaid chamber from mid means to said opening, and said means being spaceda distance from an end boundary of said chamber that is optimum formaximum radiation of power through said opening.

29. A system for the radiation of electromagnetic waves comprising adielectric guide, means for generating in said guide displacementcurrent waves of such field configuration that they are propagatedthrough said guide substantial y only at frequencies, but at any suchfrequencies, exceeding a cut-off frequency functionally related to thetransverse dimensions of the guide, said guide having a lateraldielectric connection at a distance from said generating means throughwhich said waves are radiated into space.

30. A combination for the directive radiation of high frequencyelectromagnetic waves comprising an elongated metallically boundedchamber enclosing a dielectric medium, means for producinglongitudinally progressive guided waves in said chamber of a charactersuch that the velocity of propagation is a function of a transversedimension of the chamber, said chamber having a plurality of openings inthe lateral boundary thereof for the emission and radiation of wavesguided through said chamber from said means to said openings, saidopenings being spaced longitudinally of the chamber in a mannersystematically related to the length of said waves within the chambe 31.A system for the radiation of electromagnetic waves comprising ametallic pipe and a dielectric medium enclosed thereby, means forlaunching electromagnetic waves within said pipe at a frequencyexceeding a high-pass transmission cut-off frequency below whichsubstantially no power transmission can take place, said pipe havingsystematically spaced therealong a multiplicity of lateral aperturesthrough which said waves are emitted.

32. A metal-walled chamber enclosing a gaseous dielectric medium andmeans for propagating ultra high frequency waves through said chamber.said chamber having a multiplicity of apertures systematically spacedapart in relation to the length of said waves so that said waves emittedthrough said apertures are combined and radiated with directionaleffect.

33. A combination in accordance with claim 32 in which said aperturesare provided with respective metallic horns of rectangular crosssection.

34. A combination for the radiation of electromagnetic waves comprisinga metallically bounded chamber containing a dielectric medium. aplurality of metal-sheathed wave guides having openings thereinconnecting said guides and the said dielectric medium so that highfrequency electromagnetic waves in said guides are released into saidchamber, the space-phase II prising a wave guiding structure consistingessen relations of the waves escaping from said openings being such thatthe waves combine'to produce a resultant wave having a substantiallyplane wave front, said chamber having at least one opening therein forthe radiation into space of the waves therein produced. v

35. A radiator of electromagnetic waves comtially of a metallic pipe,one end of said pipe being open, and means at the other end of said pipefor generating therein high frequency waves of such field pattern thatthey are guided through said pipe and radiated from said open endsubstantially only at frequencies above a high-pass transmissioncut-oil? frequency dependent on a transverse dimension of said pipe.

36. A radiator of electromagnetic waves com prising a wave guidingstructure consisting essentially of a metallic pipe, one end of saidpipe being open, and means at the other end of said pipe for generatingtherein high frequency waves of such field pattern that they are guidedthrough said pipe and radiated from said open end substantially only atfrequencies above a critical frequency dependent on a transversedimension of said pipe, said pipe being proportioned at said open end toeffect an impedance match, whereby said waves are radiated substantiallywithout reflection at said open end.

37. A radiator of electromagnetic waves comprising a wave guidingstructure consisting essentially of a metallic pipe, one end of saidpipe being open, and means at the other end of said pipe for generatingtherein high frequency waves of such field pattern that they are guidedthrough said pipe and radiated from said open end substantially only atfrequencies above a critical frequency dependent on a transversedimension of said pipe, the open end of said pipe being terminated in ahorn for reducing wave reflection at that point.

38. In combination, a wave guide comprising a metallic pipe, means forlaunching ultra high frequency electromagnetic waves within. said pipefor progressive transmission therethrough, one end of said pipe beingopen, and a metallic horn at the end of said pipe for the radiation ofsaid waves.

39. A combination in accordance with claim 38 in which said horn isproportioned to minimize reflection of said waves therefrom.

40. In a radio transmission system, a wave guide comprising a hollowmetallic pipe containing a gaseous dielectric medium, one end of saidpipe being open and the other closed, a metallic horn surmounting theopen end of said pipe, and means near the closed end of said pipe forlaunching high frequency electromagnetic waves within said pipe fortransmission to said horn and radiation therefrom or for receiving radiowaves intercepted by said horn and transmitted through said pipe,

41. In combination, a wave guiding structure consisting essentially ofmetallic lateral bounding means and a dielectric medium enclosedthereby, the end of said structure being dielectrically connected withfree space and said metallic means flaring as a horn, the mouth of saidhorn being of rectangular cross-section, and means at a distance fromsaid end of said structure for launching therein high frequency electromagnetic waves for transmission therethrough and radiation throughsaid mouth.

42. A combination in accordance with claim 41 in which said launchingmeans is adapted to generate asymmetric magnetic waves the electricfleld of which is aligned substantially perpendicularly to oppositesides of said hornuat its mouth.

44. In combination. a wave guiding structure consisting essentially ofmetallic lateral bounding means enclosing a gaseous dielectric medium.the end of said structure being open to free space and said metallicmeans flaring as a born, the mouth of said horn being of rectangularcross-section, and means at a distance from said end of said structureadapted either for launching therein high frequency electromagneticwaves for transmission therethrough and radiation through said mouth orfor receiving such waves entering said mouth.

45. An electromagnetic wave radiator comprising an open-headed metallicchamber, a metallic horn flaring from the open end of said chamber, ahigh frequency conductor extending transversely through the interior ofsaid chamber from one wall thereof to the other, and means for excitingsaid conductor with high frequency electromagnetic oscillations.

46. A combination in accordance with claim 45 in which said excitingmeans is electrically interposed in said conductor.

47. A combination in accordance with claim 45 in which said conductor isspaced a distance from a closed end of said chamber that is optimum formaximum radiation of power from said open end,

48. In combination, a cylindrical metallic chamber, a metallic hornsurmounting an open end thereof, and means within the chamber adaptedfor launching ultra high frequency electromagnetic waves for radiationthrough said horn or for receiving such waves transmitted through spaceand intercepted by said horn.

49. A combination in accordance with claim 48 in which said launchingmeans is adapted to generate or receive waves of asymmetric magneticfield pattern.

50. A section of metallic pipe, reflecting means closing one endthereof, a metallic horn opening from the other end and electromagneticwave launching means within said pipe and spaced .a distance from saidreflecting means that is optimum for the radiation of said waves throughsaid horn into space.

51. A cylindrical metallic chamber having one end closed and the otheropen, a metallic horn flaring from said open end, and means forgenerating ultra high frequency electromagnetic waves for directiveradiation through said horn.

52. A combination in accordance with claim 51 in which said chamber andsaid horn are of circular cross-section.

53. A radiator or receiver of electromagnetic waves comprising ametallically-bounded apertured cavity portion and a metallic hornportion around the aperture, a high frequency conductor extendingtransversely through one of said portions and means for exciting saidconductor with ultra high frequency waves or for receiving such.

waves induced in said conductor by intercepted radio waves.

54. In a radio transmission system, a section of metallic pipe, ametallic horn terminating one end thereof for the radiation orinterception of radio waves, wave reflecting means at the other end, atranslating device and means electrically coupled thereto and disposedwithin the pipe for launching or receiving ultra high frequencyelectromagnetic waves, said reflecting means and said last-mentionedmeans being spaced apart a distance that is optimum for maximuminterchange of power between said translating device and said radiowaves.

55. In a short-wave radio system, a cylindrical metallic chamber, ametallic horn flaring from one end thereof, a terminal structure withinsaid chamber adapted for launching or receiving waves of asymmetricmagnetic type, and a high frequency translating device coupled in energytransfer relation with said terminal structure. 7 H V 56. Incombination, a section of metallic pipe one end of which is open and theother closed, a metallic horn flaring from one end thereof, a highfrequency conductor spaced from said closed end and extendingdiametrally across said pipe from one side thereof to the other, andhigh frequency translating means coupled to said conductor for thereception or radiation of electromagnetic waves.

57. A metallic pipe one end of which is open and the other closed, aconductor disposed transversely within said pipe with the extremitiesthereof electrically connected with the walls of said pipe, and meansinterposed to said conductor for energizing it with high frequencycurrents, whereby at frequencies sufiiciently high progressiveelectromagnetic waves are generated in said pipe and radiated from theopen end thereof.

58. A radiator of electromagnetic waves comprising in combination, meansproviding a circular current conducting path, a diametral conductorconnected across said path, a high frequency wave source electricallyinterposed at substantially the center of said conductor, and meansspaced laterally in one direction from said conductor for efiicientlydirecting the radiation therefrom.

59. A radiator or receiver of electromagnetic waves comprising a waveguiding structure consisting essentially of a gas-filled metallic pipe,one end of said pipe being open, and means at the other end of said pipefor launching therein or receiving therefrom high frequency waves ofsuch field pattern that they are guided through said pipe substantiallyonly at frequencies above a critical frequency dependent on a transversedimension of said pipe, and means at the said open end of said pipe formodifying the directivity pattern with respect to waves radiated from,or entering,'said open end.

60. A radiator of electromagnetic waves com-,

prising a wave guiding structure consisting essentially of a metallicpipe, one end of said pipe being open, and means at the other end ofsaid pipe for generating therein high frequency waves of such fieldpattern that they are guided through said pipe and radiated from saidopen end substantially only at frequencies above a critical frequencydependent on a transverse dimension of said pipe, and means at the openend of said pipe for modifying the intensity-direction pattern of thewaves radiated therefrom.

61. In a system for the radiation of ultra high frequencyelectromagnetic waves, a wave guide comprising a metallic pipe and meansfor launching electromagnetic waves in said pipe for progressivetransmission therethrough, .said pipe having an opening at a distancefrom said launching means for the emission of said waves. said launchingmeans being adapted for the generation of waves of such field patternthat, first, they are propagated through said pipe and emitted throughsaid opening substantially only at frequencies exceeding a cut-offfrequency dependent on a transverse dimension of said pipe, and, second,substantial propagation and emission can take place at any frequencyexceeding said cut-ofi frequency.

62. A system in accordance with claim 61 in which said launching meansis adapted for waves of asymmetric type.

63. A system in accordance with claim 61 in which said launching meansisadapted for waves of asymmetric magnetic type.

64. In combination, an open-ended metallic pipe, means within said pipeand removed from the open end for launching ultra high frequencyelectromagnetic waves of such characteristic field pattern that the pipepresents to them the characteristics of a high-pass filter, thefrequency of the waves so launched being substantially in excess of thecut-off frequency, whereby said waves are propagated to said open endand radiated therefrom.

65. A combination in accordance with claim 64 in which said means isconstructed and arranged to launch waves of the asymmetric magnetictype.

66. In combination, an open-ended metallic pipe, a metallic hornsurmounting the said open end of said pipe, and means within said pipeand removed from the open end for launching ultra-high frequencyelectromagnetic waves of such characteristic field pattern that the pipepresents to them the characteristics of a highpass filter, the frequencyof the waves so launched being substantially in excess of the cut-offfrequency, whereby said waves are propagated to said open end andradiated therefrom.

67. In combination, an open-ended metallic pipe, a flaring metallicportion at the said open end of said pipe, said metallic portion beingof substantially rectangular cross-section, and means within said pipeand removed from the open end either for launching ultra-high frequencyelectromagnetic waves of such characteristic field pattern that the pipepresents to them the characteristics of a high-pass filter or forreceiving radio waves to which the pipe presents said characteristics,the frequency of the waves so launched or received being substantiallyin excess of the cut-off frequency, whereby said waves in said pipe arefreely propagated therethrough.

68. A system for the radiation or reception of electromagnetic wavescomprising an array of like-directed metallic horns, means constitutingeither a source or receiver of high frequency waves, and a metallicallybounded transmission structure connecting said means and all of saidhorns for the transfer of energy inthe form of guided waves, saidstructure enclosing only a dielectric medium and presenting to saidguided waves the characteristic of a high-pass filter.

69. A system in accordance with the claim next preceding in which saidhorns are rectangular in cross-section, whereby the waves radiatedtherefrom are more effectively combined for directive transmission.

' GEORGE C. SOU'I'HWORTE.

